Document request-scoped MySQL cleanup

src/wasm/worker.cpp

@@ -799,7 +799,9 @@ public:
 
 #ifdef UCE_WASM_HOST_CONNECTORS
 	// Host-owned resource handle table (§3.1): connections opened by the guest
-	// live here and are closed when the workspace drops at request end.
+	// live here and are closed when the workspace drops at request end. This is
+	// the wasm-side enforcement of request-scoped DB lifecycle; app code should
+	// never cache these opaque handles across requests.
 	std::vector<SQLite*> sqlite_handles;
 	std::vector<MySQL*> mysql_handles;
 #endif